Glyceric acid is readily available material. It would therefore be a great advantage to design a surfactant based on the material; particularly a surfactant which can enhance and stabilize foam. Unexpectedly, it has been found that the N-alkylglyceramides of the invention, when used in combination with other surfactants, meet this criteria.
There are a number of compounds in the art which have some structural similarities to the alkylglyceramides of the invention.
Alkanolamides, for example, are a well-known class of compounds which have, of course, both an alcohol and an amide functional group. These compounds both enhance and stabilize foam. These compounds are structurally different from the N-alkylglyceramides of the invention. Specifically, the alcohol group is attached to the amine rather than the carbonyl group, i.e., it is not a sugar acid compound and is clearly not based on glyceric acid. Finally, there is certainly no teaching or suggestion of using the compounds of the invention as cosurfactant with other detergent actives to provide enhanced foaming.
U.S. Pat. No. 5,009,814 to Kelkenberg et al. teach N-polyhydroxyalkyl fatty acid amide compounds having the formula ##STR2##
where R.sub.1 is alkyl R.sub.2 is hydrogen, alkyl group or alkylene oxide and X is a polyhydroxyalkyl group. Again, in these compounds, the polyhydroxyalkyl group is attached to the nitrogen atom rather that the carbonyl group.
Thus, there is no teaching or suggestion in the art of the specific N-alkylglyceramide compounds of the invention. Further there is no teaching or suggestion that the compounds of the invention can be used as cosurfactants to enhance and stabilize foam.
Applicants have also filed a copending application entitled "Compositions Comprising Nonionic Glycolipid Surfactants" a continuation of U.S. Ser. No. 816,419, which teaches the use of certain sugar compounds, i.e., aldobionamides (such as lactobionamides) in personal product or detergent compositions. These compounds are sugar based compounds which are not based on glyceric acid such as the compounds of the subject invention.
French Patent No. 82/05005 (Publication No. 2,523,962) teaches amides having the formula EQU HOCH.sub.2 (CHOH).sub.m CONHR
in which m is 2 to 6 and R is a linear or branched alkyl group having 6 to 18 carbons.
In these compounds, m must equal at least 2 and, therefore, these are not amides of glyceric acid. Thus, there is no teaching or suggestion of using glyceric acid amides (alkylglyceramides). Again, there is also no teaching or suggestion that alkylamides may be used as cosurfactants with other detergent actives.
Accordingly, it would be greatly desirable to find novel surfactants based on a readily available compounds, such as glyceric acid. It would be further desirable to produce such a surfactant which, when used in combination with other surfactants, is useful as a foam enhancer and stabilizer. Finally it would be desirable to find such a surfactant which can be used in personal product and detergent compositions.